Object Oriented Programming (OOP) is a programming paradigm that’s the cornerstone of recent software program improvement. Whereas OOP isn’t the one programming paradigm that exists, I’d argue it’s a very powerful to have a agency basis of, and when used accurately, can result in stronger and extra sturdy software program. However what’s OOP and how will you make certain to know it nicely? Let’s discover.
At a excessive degree, in OOP there are 3 principal pillars to know for getting OOP down:
- Encapsulation with lessons
- Polymorphism (a very powerful by far)
Encapsulation is the flexibility to surround knowledge that describes the thing and the features used to control that knowledge into one module container.
In OOP these are sometimes known as lessons and are on the heart of the paradigm. The ensuing variable when the variable is said is known as an object. An vital half is abstraction in order that solely mandatory options are uncovered.
- Non-public/Inside: Strategies and properties are accessible from different strategies of the identical class. Something outdoors of the category shouldn’t be capable of entry these members/strategies. That is sometimes denoted by Non-public or Protected.
- Public/Exterior: Strategies and properties are accessible from outdoors the category.
An instance can be if you happen to have been programming a card sport. In your card dec class, would you need another person to change the variety of playing cards within the deck? Most likely not.
Inheritance is the flexibility to take an present class and lengthen its performance to type one other class.
Why is that this vital? As a result of it helps reusability with code reuse. It is because the brand new class has entry to the entire mother or father performance. The kid class simply wants so as to add new attributes and strategies which can be particular to its wants.
- Generalization is the relation such that the subclass is a variation of the mother or father. I.e. a pickup truck “is-a” vehicle.
- Specialization is the connection such that the category “has-a” subclass. I.e. an vehicle “has-a” engine.
Polymorphism is the flexibility of comparable objects to reply in a different way to the identical message.
The ultimate pillar of OOP is carefully associated to inheritance and but is arguably way more vital. The prefix poly means many; morph means type. Polymorphism then refers back to the means of a single kind or class to take many varieties.
How is that this carried out? With methodology overriding:
Within the instance above, you’ll be able to see that each the electrical automobile and the pickup truck inherit from Car and each override the Begin habits since each have vastly completely different wants. An electrical automobile doesn’t want to begin an engine whereas a pickup truck would (assuming it’s of the fuel selection).
- Nicely designed objects manipulate the information or state of an object by passing messages via the thing’s interface.
- Controlling an object via its interface ensures it behaves in a protected method and that the inner state stays legitimate.
- The flexibility to mannequin the true world is a crucial benefit of OOP.
- Objects have to be self-contained in order that they will stand on their very own.